Well my tunnel is quite a bit different than the tunnels I've seen so far as it's a railroad tunnel and is a live tunnel. I was very nervous riding thru it and couldn't help looking behind me while going thru.

The tunnel is about 1/2 mile long and is on a curve so you can't see thru it. It goes thru tunnel hill near Tunnelton, Indiana.

Here's a really cool train tunnel. I took these pics aboutv 15 years ago when riding across Canada. Maybe one of our Canadian adventurers can help me out here as I can't remember exactly where this was. I do know I was near Banf.

seems the trains could not handle the grade so they tunnel inside the mountain and loop thier way up. The top photo shows the train going in the mountain at the bottom and approaching above. The lower photo shows the train actually crossing over itself. Kind of neat. Lots of tourists were waiting to see this specific train go through, we just happened to show up about 5 minutes before it got there.

This train tunnel is in south Alabama. I have a geocache hidden here and run a dualsport ride through here a couple times a year. Finished in 1899 with simple tools, the tunnel is 840 feet long. Now home to lots of little bats.
Plenty of hurricane debri thanks to Ivan and Denise
You can sometimes hear the Bats gnashing their little teeth in here